DoH: introduce manual read timer control

This commit introduces manual read timer control as used by StreamDNS
and its underlying transports. Before that, DoH code would rely on the
timer control provided by TCP, which would reset the timer any time
some data arrived. Now, the timer is restarted only when a full DNS
message is processed in line with other DNS transports.

That change is required because we should not stop the timer when
reading from the network is paused due to throttling. We need a way to
drop timed-out clients, particularly those who refuse to read the data
we send.

(cherry picked from commit 609a41517b1631c320876a41c43c68c9a0ee0f9f)

diff --git a/lib/isc/netmgr/http.c b/lib/isc/netmgr/http.c
index f48841856ab301f9788e4bc504a5e4a2f5402f48..d3e84b6602838851c050e9a56cca5846f5b69404 100644 (file)
--- a/lib/isc/netmgr/http.c
+++ b/lib/isc/netmgr/http.c
@@ -555,6 +555,7 @@ finish_http_session(isc_nm_http_session_t *session) {
                if (!session->closed) {
                        session->closed = true;
                        isc_nm_cancelread(session->handle);
+                       isc__nmsocket_timer_stop(session->handle->sock);
                }
 
                /*
@@ -686,6 +687,9 @@ call_unlink_cstream_readcb(http_cstream_t *cstream,
        isc_buffer_usedregion(cstream->rbuf, &read_data);
        cstream->read_cb(session->client_httphandle, result, &read_data,
                         cstream->read_cbarg);
+       if (result == ISC_R_SUCCESS) {
+               isc__nmsocket_timer_restart(session->handle->sock);
+       }
        put_http_cstream(session->mctx, cstream);
 }
 
@@ -1548,6 +1552,7 @@ http_do_bio(isc_nm_http_session_t *session, isc_nmhandle_t *send_httphandle,
        if (nghttp2_session_want_read(session->ngsession) != 0) {
                if (!session->reading) {
                        /* We have not yet started reading from this handle */
+                       isc__nmsocket_timer_start(session->handle->sock);
                        isc_nm_read(session->handle, http_readcb, session);
                        session->reading = true;
                } else if (session->buf != NULL) {
@@ -1604,6 +1609,7 @@ http_do_bio(isc_nm_http_session_t *session, isc_nmhandle_t *send_httphandle,
                } else {
                        /* Resume reading, it's idempotent, wait for more */
                        isc_nm_resumeread(session->handle);
+                       isc__nmsocket_timer_start(session->handle->sock);
                }
        } else {
                /* We don't want more data, stop reading for now */
@@ -1788,6 +1794,7 @@ transport_connect_cb(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
        }
 
        http_transpost_tcp_nodelay(handle);
+       isc__nmhandle_set_manual_timer(session->handle, true);
 
        http_call_connect_cb(http_sock, session, result);
 
@@ -2405,6 +2412,8 @@ server_call_cb(isc_nmsocket_t *socket, const isc_result_t result,
        handle = isc__nmhandle_get(socket, NULL, NULL);
        if (result != ISC_R_SUCCESS) {
                data = NULL;
+       } else if (socket->h2.session->handle != NULL) {
+               isc__nmsocket_timer_restart(socket->h2.session->handle->sock);
        }
        if (result == ISC_R_SUCCESS) {
                socket->h2.request_received = true;
@@ -2846,6 +2855,8 @@ httplisten_acceptcb(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
        isc__nmsocket_attach(httplistensock, &session->serversocket);
        server_send_connection_header(session);
 
+       isc__nmhandle_set_manual_timer(session->handle, true);
+
        /* TODO H2 */
        http_do_bio(session, NULL, NULL, NULL);
        return ISC_R_SUCCESS;